IANS

Sao Paulo/Paris, Jun 6: The mystery surrounding the fate of the Air France flight that crashed into the Atlantic earlier this week deepened after Brazilian officials admitted that no trace of the plane or its 228 occupants had been recovered.

Bad weather and poor visibility hampered the ongoing search Friday for the wreckage of the ill-fated Airbus A330-200, which vanished early Monday on a flight from Rio de Janeiro to Paris.

France said it would send a submarine to the area in hopes of finding the elusive black boxes that could solve the question of what happened to the plane. An apparent breakthrough in the investigation fell through late Thursday when a Brazilian official said debris fetched from the sea was not from the airliner, as they had earlier believed.

Still rescue teams remained convinced that other debris spotted at sea did belong to the missing plane, said Brigadier Ramon Cardoso, director of the Brazilian Air Force's Airspace Control Department.

"We have located kerosene stains, a seat, some fragments of the aircraft, wires and pieces of the internal part of the plane," said Cardoso.

However, he said those fragments had already been carried off by strong currents and an attempt was now being made to retrieve them.

Late Thursday, Cardoso said that pieces of wreckage fished out of the sea did not come from the plane, as had been announced earlier in the day. A wooden palette plucked from the waters by a helicopter was "100 percent" not from the Airbus A330-200 that disappeared while on flight from Rio de Janeiro to Paris, he said.

A kerosene slick spotted in the sea also did not stem from the aircraft, but was in fact oil from a ship.

French Defence Minister Herve Morin said that Paris was sending a nuclear-powered submarine to the search area, some 1,200 kilometres off the coast of Brazil, because it is equipped with extremely sensitive sonar detectors.

"(It) can help find the black boxes," Morin said.

He said a terrorist bomb remains a possible cause for the disappearance of the jetliner.

"We have no right to exclude terrorism," Morin told journalists in the French capital. "But we have no element or trail that would permit us to corroborate that."

He noted that he had not heard of any threats to the flight or of any group or individual claiming responsibility for bringing the aircraft down.

"But in most cases of terrorist acts against airplanes, there were no claims of responsibility," Morin said.

At the same time, the French Office of Accident Investigations and Analyses (BEA), which is leading the investigation into the disaster, issued a statement warning against "any hasty interpretation or speculation on the basis of partial or unconfirmed information."

At the current stage of the inquiry, investigators have only established two facts about the crash, the BEA said. One was "the presence near the airplane's planned route over the Atlantic of significant convective cells typical of the equatorial regions", suggesting stormy weather at the time of the crash.

In addition, "based on the analysis of the automatic messages broadcast by the plane, there are inconsistencies between the various speeds measured," the BEA said.

French Junior Transport Minister Dominique Bussereau on Friday urged "extreme caution" in regard to the fragments fished out of the waters.

"I remind you that our airplanes and our ships have seen (no wreckage). It is our Brazilian friends who have seen things which they...said came from the plane," Bussereau told RTL radio.

Air France said Friday that, because of the accident, it will redesignate its route from Rio de Janeiro to Paris.

Formerly designated as flight AF 447, the route will be known as AF 445 starting on Sunday, an Air France spokesman told DPA.

A mass was held Friday in Rio de Janeiro to remember the missing airliner, but Brazilian President Luiz Inacio Lula da Silva declined to take part. Presidential advisers told the state news agency ABR that Lula would "seek other ways to honour" the victims of the presumed crash.

The accident happened while Lula was beginning a Central American tour in El Salvador. However, Lula did not cancel planned visits to Guatemala and Costa Rica, and he only returned to Brazil in the early hours of Thursday.

He also skipped Thursday the multi-religious service that gathered about 1,000 people Thursday in Rio de Janeiro, including Kouchner and Brazilian Foreign Minister Celso Amorim.

Thirteen relatives of some of the passengers were in the northeastern Brazilian city of Recife to monitor the rescue efforts and seek answers.